Microelectromechanical system (MEMS) sensor devices are often sealed within a cavity to protect fragile, moving structures. But some types of MEMS sensor devices are designed to be unsealed to enable the structures to interact with the surrounding environment. For example, a diaphragm of a MEMS capacitive pressure sensor device is typically exposed to the surrounding environment in the interest of developing an accurate indication of the ambient pressure level.
MEMS sensor devices are usually fabricated via surface micromachining procedures. The procedures are configured to produce mass quantities of the MEMS sensor devices on a wafer. The wafer is eventually sawed or diced into numerous individual die. Water is often used to cool the saw blade during dicing. Water may also be applied to the wafer to remove debris generated during dicing.
When MEMS sensor devices lack a protective cavity, the water used for saw blade cooling and wafer cleaning may impinge upon the fragile structures of the sensor devices. MEMS device structures, such as pressure sensor diaphragms, may be damaged as a result of such contact with the water or other debris created during the dicing process.